Investments - Current and Non-current of Available-for-Sale Debt Securities (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Reported under the following captions in our consolidated balance sheets:
Total	$ 3,275.9	$ 3,042.7
Cash and cash equivalents
Reported under the following captions in our consolidated balance sheets:
Current available-for-sale debt securities	162.4	21.5
Current marketable investments
Reported under the following captions in our consolidated balance sheets:
Current available-for-sale debt securities	1,402.8	1,545.9
Non-current marketable investments
Reported under the following captions in our consolidated balance sheets:
Non-current marketable investments	$ 1,710.7	$ 1,475.3

No definition available.

Name:	us-gaap_AvailableForSaleSecuritiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479130/326-30-45-1

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), classified as current.

+ References

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterestCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

+ References

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterestNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_CashAndCashEquivalentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=uthr_MarketableSecuritiesCurrentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=uthr_MarketableSecuritiesNoncurrentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: